Outline - 4, BIO 3360, Respiration III - Non-Mammalian Air Breathing Animals
I. Other air breathing animals
A. Birds
1. Trachea
2. Bronchi
a. Several secondary bronchi connected by thousands of parabronchi
b. Gas exchange occur between the air in the air capillaries of the parabronchi and the blood capillaries
c. Tremendous surface area and continuous air flow through parabronchus in one direction during both inspiration and expiration
3. Air sacs provide continuous ventilation, with fresh air moving primarily into air sacs and then air sacs ventilating the parabronchi.
B. Reptiles
1. Use negative pressure like mammals to inspire but don't have a diaphragm
2. Elastic recoil produces expiration
C. Amphibians
1. Cutaneous and buccal respiration
2. Lungs for some
a. Lung may be non compartmentalized and poorly vascularized
b. Compartmentalized and well vascularized
c. Frogs ventilate by pulse pump or force pump
D. Insects - Tracheal System
1. Tracheal systems are air filled tubes that travel from body surface to cells
a. Gases move fast
b. Tubes are invaginations of cuticle
c. Spiracles (tracheal entrances) can adjust to control air flow
d. Tracheoles are blind-ended tubes near cells
2. Tracheal Ventilation
• In small insects diffusion of the gases in the tracheas is rapid enough .
• Flying insects use ram ventilation or draft ventilation to ventilate tracheae.
• Larger insects and small insects during increase metabolic activity need to add convection (ventilation).
• Air sacs and tracheas are compressible and their volume changes with respiratory movements (compression and expansion of the body wall, specially the abdomen).